Manufacture of hydrogen by partial liquefaction of gaseous mixtures



@mm 1924. wnmw G. CLAUDE MANUFACTURE OF HYDROGEN BY PARTIAL LIQUEFACTION 0F GASEOUS MIXTURES Filed Feb. 9, I922 I N VEN TOR.

@ w BY '1;

w ATTORNEY/.8

cannons citauioa, or rants, a r

0E, ASSIGNO'R T0 SOCIETE LAIR LIQUIDE (SOGIETE ANONYME POUR LETUDE ET LEXPLOITATION DES JPROGEDES GEORGES CLAUDE),

1 01E PARIS, FRANCE.

MANUFACTURE OF HYDROGEN BY PAJRETAL LIQUEFACTIO'N OF GASEOU B HI iojs. T'Ufi Application filed February 9, 1922. Serial No. 535,191.

To all whom it may concern: 7

Be it known that I, GEORGES CLAUDE, a citizen of France, residing at Paris, in the Republic of France, have invented certain new and useful Improvements in the Manufacture of Hydrogen by Partial Liquefaction of Gaseous Mixtures; and l do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relatesto a process and apparatus for the separation of gaseous mixtures, and particularly to the recovery of hydrogen by partial liquefaction of preliminarily purified mixtures containing the same, such as water gas, ordinary illuminating gas as used for town lighting, cokeoven gas and similar gases, in whlch the source of cold, compensating for losses in the system, is supplied by the expansion with external work of thecompressed hydrogen after it has been subjected to the lowest temperature of the cycle, as described more especially. in French Letters Patent No. 329,839 of the 28th February, 1903, United States Letters Patent No. 1,212,455, and the specification of the copending application Serial No. 527,542

1n the process and apparatus described in the specifications of .the patents referred to above, it is essential to comply with two con-.

ditionsz-(l) to ensurethe maintenance of the necessary quantity of liquid While using an initial pressure which is as low as possible, and (2) to obtain a very high degree of purity in the hydrogen by sub ecting it to r a very low temperature and to the total pressure.

The first condition asumes that the expansion with external work is as eflicacious as possible, and to ensure this it is necessary, as has been explained in the patent speci fications hereinbefore referred to, to carry out this expansion at the highesttemperature compatible with the temperature conditions of the gas after expansion necessitated by the degree of purity it is desired to obtain, more especially as, in default of this step, all of the other gases would be solidified by the very low temperature of the hydrogen. tVith this object in view, and in accordance with the method of working described in the prior specifications mentioned, the compressed hydrogen is heated, before sending it into the expander, by passing it through a liquefier, through which is circu lated in the reverse direction a part of the gases to be treated after their exit from the cold end of the temperature exchanger, thesev gases being afterwards returned to the liquid collector of the separating column. It is, moreover, desirable for these gases to arrive at the liquefier from the temperature exchanger as warm a spos'sible, and this presupposes that the expanded hydrogen and the carbon-monoxide, or carbon-monoxide,

nitrogen and methane, before being sent to the temperature exchanger are themselves also previously heated by other parts of the compressed gas treated in supplementary liquefiers, as set forth in particular in the specification of the copending application Serial No. 527,542.

These, supplementary liquefiers, however, form a somewhat complicated group of apparatus, and their weight and additional losses of cold due thereto tend to minimize.

certain of their advantages.

A much simpler arrangement of apparatus, which forms one of the chief objects of the present invention ensures all the advantages of these multiple liquefiers, while retaining only that for the heating of the rangement to be described ermits of a considerable increase in the initial temperature of the expansion, this being brought about by considerably heating the compressed hydrogen prior to its expansion, and it also at the same time permits of a very considerable reduction in the temperature at which the gases enter the nest of tubes wherein they are subjected to treatment, as alsoan increase of the proportion of gas already liquefied in those entering gases.

According to the present invention the manufacture of hydrogen by partial liquefaction of mixtures of gases containing the hydrogen prior to its expansion; the arsame, such as water gas, ordinary illuminating gas, or coke oven gas and similar gases is effected by a process in which the fraction of the compressed gasses utilized for feeding the liquefaction, wherein the compressed hydrogen is heated prior to its expansion, is withdrawn from the temperature exchanger 0r exchangers at a point located at such adistance from thecold end of said exchanger or exchangprs that the temperature attained by the ydrogenimmedlately vbefore subjecting it to. ex ansion accomand at the same time the temperature of the main portion of the gases to be treated ad- 'mitted to the separating column s considerabl lowered.

I In or er that the-invention may be clearly understood and readily :carried into effect,

the same will-now be. described more fully with reference tothe accompanying drawing which shows diagrammatically an arrange-- v ment ofapparatus suitable for carrying out the present process.

- AS,Sl]. OWI1 by the drawing, "it is convenient to useonly one temperature exchanger -E, of the same type asthose commonly emplayed in air-liquefaction apparatus. The

whole ofthe com re'ssed as to be treated circulates roundt e outsi e of the nest of t'ubesinthe temperature exchanger E, the 'gas following the path -desired round the tubes by means of suitable baflle plates E,

j whilst the separated gases, for example hydrogen and carbon-monoxide in the case of water gas, or hydrogen, carbon-monoxide and nitrogen, and methane inthe case of coke oven gas, pass into the tubes from their several respectlve collectors in two or three separate fractions, as the case -may be.

- .Such an exchanger E havingtwo'compartments is shown diagrammatically in the accompanying drawing, this being assumed to be for use in the case of water gas, which enters the exchan er through the pipe H.

In the case of t e, present arrangement of A apparatus, therefore, the fraction of the com ressed gases to be treated which is.in-.

ten ed for feeding the liquefier .L (that serves as a heater for thecompressed hydrogen is drawn ofi not from, the-coldest end 0f t eexchan er E, but-at .a certain distance fromthis col end, namely at -The separated gases, hydrogen and car-' bonmonoxide, forymstan'ce, arrive directly from the separating column M at the inlets B and G into 'theexchanger E, without undergoing any previous heating in liquefiers.

i After passingl'throu h the tu es of the ex-' theoutlets J and K.

changer the separate gases pass-pd through The gases .drawn ofl" at A, which feed the liquefierL, are clearly much less cold than those which reach the end .G of the exchanger. A sufiicient proportion of these compressed gases, which are cooled only to a small extent, is made to circulate in the liquefier L, whilst at the same time the valve V, through which the enter the nest of tubes ases to be treated in the separating column M, is gradually adijusted to the ex tent necessary to allowsu cient heating of the compressed hydrogen which circulates in the other compartment of the liquefierL on its way to the expander N. This heating is measured, for example, by thermo-electric couples or bye differential couple. The result desired is thus attained without further difliculties; namely, while the heating of the compressed hydrogen prior to expansion is very great, the cooling of the remainder of the compressed gases which circulate in the exchanger right u to the cold end G, is also very reat an very efiicacious, as this fractiono the total quantity of gases treated circulates in the reverse direction to a quantity of very cold carbon-monoxide and hydrogen equal to the total output from the apparatus. Consequently these ases which leavethe exchanger at Gr reach t e collector D' in a very cold state and partly liquefied, the result of which is to reduce the evaporation of the liquid at the exterior of the tubes F and facilitate the maintenance of the liquid in the separating column. Furthermore, it maybe pointed out that the single liquefier L is specially suited for satisfactory working, as the fluids which circulate therein are all of them at the maximum pressure of the cycle.

The more important and novel features of the invention being understood from the foregoing description, we shall now describe the operation in more detail. The gaseous mixture under the required pressure is introduced to the exchanger E through the inlet H and circulates downwardly in a sinuous path about the bafiies E, and the tubes E bein thereby cooled by indirect contact with t e gaseous roducts passing upwardly through the tu es. The major portion of thegaseous mixture escapes partly liquefied from the exchanger at G and, un-

der" control 'of the valve V, is delivered to the collector D at the foot of the column M. Thence the gaseous mixture passes upwardly through the tubes F and is therein subjected to indirect contact with liquid accumulating in the column and in a collector M which issupportedabove the principal body of the liquid. The liquid surrounding the tubes F'is vaporized, and the gaseous mixture in the tubes is subjected to selective liquefaction with backward return of the liquid in contact with the incomin gaseous mixture, whereby the liquid formed is enriched in the less volatile constituent of the gaseous mixture. The liquid returns to the collector D and is thence delivered through a pipe 1) controlled by a valve D" to-the collector M" from which it overflows to the principal body ofliquid in the col- The unliquefied residue. of the gaseous mixture continuing through the tubes -'F retrace in the lower sections of the'tubes lF and finally entering the collector l). The residual unliquefied gas is withdrawn through the pipe R and is conveyed thereby to the liquefier L wherein it circulates upwardly about the bafiies S in indirect contact with a portion of the original gaseous mixture flowing downwardly through tubes T in the liquefier and supplied through a pipe N from the outlet A of the exchanger E. This is the regulated portion ofthetoriginal gaseous -mixture partially cooled in the exchanger E, but not reduced to the temperature of that portion which escapes from the exchanger at G, and after passing through the tubes T, the liquid formed in the liquefier, together with any unliquefied gas, es-.

capes through the pipe W to the collector D. The residual gas, after passing through the exchanger L, is delivered by a pipe X to the expander N where it expands with external work and is thereby cooled. Thev cold gaseous residue is delivered by a pipe Y to the upper section of the column where it circulates about the battles P as hereinbefore described, escaping through a pipe Z to the inlet B of the exchanger E. The vapor formed in the lower compartment of the column escapes through a pipe Q to the inlet C of the exchanger and the separated gaseous products, after passing through the tubes E of the exchanger, escape at J and K respectively.-

The initial filling of the apparatus is effected, for example, by passing the gases to be treated into the expander N by way of the valve V which is closed when the column is in operation, the portions liquefied by the action of the expansion toward its end passing into the upper part of the separating column and thence by way of the valve V also normally closed, into the lower part of the said column, the

'is the same, and the calorific capacity of the hydrogen in a compressed state increases by the whole of that of the impurities to be liquefied.

The compressed hydrogen, after leaving the tubes through which it circulates in counter current to the expanded hydrogen circulating outside the said tubes, cannot, 7

therefore, attain as low a temperature as the expanded hydrogen, whence the necessity arises of arranging matters so that the hydrogen, as a result of its expansion, attains a temperature which is as low as pos-v sible. This, however, as is well known, leads to difficulties owing to the possible solidification of the remaining impurities and the lubricants that it maybe necessary to employ. v

lln accordance with the present invention, this difliculty is overcome, when the presence of nitrogen is notprejudicial, by adding through a pipe T to the compressed hydrogen, just when it is about to expand, a suitable proportion of dry cold nitrogen which mixes with this hydrogen and expands with it, and becomes liquefied at the end of the expansion.

The calorific capacity of the expanded hydrogen is thus increased by the whole of that of the nitrogen, (which is partly liquid) carried along with it, and the current of expanded hydrogen is thus able to bring the counter current of compressed hydrogen to be purified to a lower temperature, starting from one and the same final temperature of expansion.

Furthermore, the liquid nitrogen thus formed plays an important part as a lubricant in connection with the working of the expander. There may also, if desired, be added to the nitrogen hydrocarbons which do not solidify under the temperature conditions obtaining in the expander.

While the invention has been described with reference particularly to the separation of hydrogen and its recovery from gaseous mixtures, the fundamental principles of the method and apparatus may be applied with beneficial results to the separation of gaseous mixtures other than those mentioned.

Moreover, as will be apparent from the foregoing description, various changes may be made in the details of the method and apparatus without departing from the invention or sacrificing any of the several advantages thereof.

I claim:

1. A process for the manufacture of hydrogen by partial liquefaction of mixtures of gases containing the same, such as water gas, ordinary illuminating gas, or coke oven gas, in which the fractionof the compressed gases utilized for feeding the hquefier. wherein the compressed hydrogen is heated prior to its expansion with production of external work, is withdrawn from the tempera-tureexchanger or exchangers at a point located at such a distance from the cold end of said exchanger or exchangers that'the temperature attained by the; hydrogen immediately before subjecting it to expanslon is raised to the maximum degree compatible withthe low temperature after expansion necessary to ensure purity of the hydrogen, and the cold hydrogen after expansion is circulated in heat-exchanging relation with the residual, gas resulting from partial liquefactionof the gaseous mixture to en sure maximum separation of impurities from the hydrogen in the residual gas.

2. A process for the manufacture of hydrogen by partial liquefaction'of mixtures of gases containing the same, such as water gas, ordinary illuminating gas, or. coke ovengas, in whichthe fraction of the compressed gases utilized for feeding the liquefie-r wherein the compressed hydrogen is heated prior to its expansion with the production of external work is withdrawn from the tempera- ,ture exchanger or exchangers at a point located at such a distance from the coldv pansion necessary to ensure purity of the end of said exchanger or-exchangers' that the temperature attained by 'thehydrogen immediately before subjecting it to expansion is raised to the maximumdegree compatible with the low temperature after'exhydrogen, while at. the same time the temperature of the main portion of the gases admitted of the separating column is consideiably lowered and acertain proportion of cold compressed nitrogen is added to the compressed hydrogen before the latter is expanded. v

-3. A process for the manufacture of hydrogen by partial liquefaction of I mixtures of gases containing the same, such as water gas, ordinary illuminating gas, or coke oven gas, in which the fraction ofthe com-v pressed gases utilized for feeding the liquefier wherein the compressed hydrogen is heated prior to its expansion with the production of external work is withdrawn from the temperature exchanger or exchangers at a point located at such a distance from the .coldend of'said exchanger orexchangers that the temperature attained by the hydrogen immediately before subjecting it to expansionis raised to the maximum degreecompatible-With the low .temperature after expansion-necessary. to ensure purity of the hydrogen, while 'at thesame time the. tem-' perature of the main portion of thegases admitted to the separating column is considerably lowered and a certain proportion of hydrocarbons which .do not solidify under the temperature conditions obtaining in the expander are added with nitrogen to the hydrogen before expansion thereof.

n 4. A process of separating the constitucuts of aseous mixtures such as those. containing ydrogen, comprising initially coolmg the compressed gaseous mixture by indirect contact with gaseous products of the residual ture and then with the other gaseous products of the separation for the cooling ofthe gaseous mixture.

5. A process of separating the constituents of aseous mixtures such as those containing hy rogen, comprising initially cooling the compressed gaseous mixture by indirect contact with'gaseouscproducts of the separation, withdrawing part 'ofthe cold gaseous mixture, further cooling'th'e remaining .cold gaseous mixture till a partial liquefaction occurs by indirect contact with the cold gaseous products ofthe separation, subjecting the gaseous mixture to selective liquefaction and to .a final purification cooling to produce a liquid and a residual gas, withdrawing and warming the residual as,

by indirect. contact with the above withdrawn Y part of the cold gaseous mixture which becomes partly liquefied, expanding the heated residual gas and utilizing this expanded residual gas first for the final 1 purification cooling'of the gaseous mixture and then with the other gaseous products of the separation for the cooling of the gaseous mixture. v

6. Aprocess of separating. the constituents of gaseous mixtures such as those containing hydrogen, comprising initially cooling the compressed gaseous mixture by indirect contact with gaseous products of the separation, withdrawing part of the cold gaseous mixture, further cooling the remaining coal gase-.

ous mixture by indirect contact with the cold gaseous products of the separation, subjectmg the gaseous mixture to selective liquefaction to produce a liquid and a residual gas, withdrawing and warming the residual gas by indirect contact with the above withdrawn part of the cold gaseous mixture, mixing another gas with the residual gas, expanding the mixed gas and utilizin the cold expanded mixed gas in the final cooling of the gaseous mixture before withdrawal of the purities therefrom. v

7. A process of separating the constituents of gaseous. mixtures such as those containing hydrogen, comprising initially cooling the compressed gaseous mixture by indirect contact with aseous'products of the separation, withdrawing part of the cold gaseous mixgas to promote the separation of imture, further cooling the remaining cold gaseous mixture by indirect contact with the cold gaseous products of the separation, subj ecting the gaseous mixture to selective liquefaction to produce. a liquid and a residual gas, withdrawing and warming the residual'gas by indircct contact with the above withdrawn part of the cold gaseous mixmixture ture, mixing another gas and liquid hydrocarbon with the. residual gas, expanding the mixed gas and utilizing the cold expanded mixed gas in the final cooling of thegaseous mixture before withdrawal of the residual gas to promote the separation of impurities therefrom.

8'. Inan apparatus for separating the constituents of gaseous mixtures such as those containing hydrogen. the combination of means for subjecting the mixture to selec-' tive liquefaction and to a finalpurification cooling to separate a liquid and a residual gas, means for initially cooling the gaseous mixture, means for withdrawing a portion of the gaseous mixture from said cooling means before it is subjected to the temperature at the colder end thereof, means for warming the residual gas by indirect contact with said ortion of the gaseous mixture, and means or expanding the warmed residual gas and means for utilizing this expanded residual gas first for the finalpurification cooling of the gaseous mixture and thenwith the other gaseous products of the separation for thecooling of the gaseous mixture, the expanded residual as in the final cooling of the ,gaseous efore withdrawal of the residual gas to promote the separation of impurities therefrom. w

9. In an apparatus for separating the constituents of gaseous mixtures such as those containing hydrogen, the combination of means for subjecting the mixture to selective liquefaction to. separate a liquid and a residual gas, means for initially cooling the gaseous mixture, means for withdrawing a portion of the gaseous mixture from said cooling means before it is subjected to the temperature at the colder end thereof, means for warming the residual gas by indirect contact with said portion of the gaseous mixture, meansfor mixing another gas with the warmed residual gas, and means for expanding the warmed residual gas, and means for utilizing the expanded residual gas in the final cooling of the gaseous mixture before withdrawal of the residual gas to promote the separation of impurities therefrom.

10. A process of separating the constituents; of gaseous mixtures such as those conta mng hydrogen by circulating it in a laterally confined space inindirect contact with the gaseous products of the separation, withdrawing from the said space part of the cold gaseous mixture, further cooling the remaining cold gaseous mixture till partial liquefaction occurs by circulating it in the continuation of the laterally confined space in indirect contact with the cold gaseous products of the separation, withdrawing the resulting liquid and gaseous mixture towards faction the cold expanded gas and the liquid parts obtained.

11. A process of separating the constituents of gaseous mixtures such as those eontaining hydrogen, comprising initially cooling the compressed gaseous mixture by in direct contact with gaseous products of the separation, withdrawing part of the cold gaseous mixture, furthercooling the remaining cold gaseous mixture by indirect contact with the cold gaseous products of the separation, subjecting the residual gaseous mixture to selective liquefaction to produce /liquid parts and a residual gas, withdrawing and warming the residual gas by indirect contact with the above withdrawn part of the cold gaseous mixture, mixing another gas with the residual gas, expanding the mixed gas and utilizing the cold expanded mixed gas and the liquid parts obtained in the selective liquefaction of the gaseous mixture.

12. A process of separating the constituents of gaseous mixtures such as those containing hydrogen, comprising initialy cooling the compressed gaseous mixture by indirect contact with gaseous products of the separation, withdrawing part of the cold gaseous mixture, further cooling the remainingcold gaseous mixture by indirect contact with the cold gaseous products of the separation, subjecting the residual gaseous mix-. ture'to selective liquefaction to produce liquid parts and a residual gas by indirect contact with the above withdrawn part of the cold gaseous mixture, mixing nitrogen with the residual gas, expanding the mixed gasand utilizing the cold expanded mixed gas and the liquid parts obtained in the selective liquefaction of the gaseous mixture.

- 13. A process of separating the constituents of gaseous mixtures such as these containing hydrogen, comprising initially cooling the compressed gaseous mixture by indirect contact with gaseous products of the separation, withdrawing part of the cold gaseous mixture, further cooling the remaining cold gaseous mixture by indirect contact with the cold gaseous products of the separation, subjecting the residual gaseous mixture to selective liquefaction to produce liquid with the above withdrawn part ofthe cold gaseous mixture,- mixing another gas and liquid hydrocarbon with the residual gas, ex-

1 6 pending the mixed gas and utilizing the cold expanded mixed gas and the liquid parts obtained in the selective liquefactlon of the gaseous mixture.

14:. A process of working'an expansion en-- '10 agine for low temperatures with a gas which does not liquefy under. the conditions revailing during the expansion such as by r0.-

gen,'which comprises adding to this gas-a gas whichliquefiesunder the conditions pre vailing during the expansion such as nitrogen. 15. A process ofworking-an expansion engine for low temperatures with a gas which does not liquefy under the conditions prevailing during the expansion such as hydrogen," which comprises adding to this gas a gas which liquefies under the conditions prevailing during the'expansion such as nitrogen andavoidin'g lubricating matter for the piston cylinder of the expansion engine. 25 i i In testimony whereof I aflix my signature.

GEORGES CLAUDE. 

